Small gull with distinctive bold "M" pattern on wings in flight, formed by black outer primaries, white inner flight feathers, and dark back. Breeding adults have dark gray head and black bill with yellow tip. Nonbreeding adults have similar distinctive bill but with a mostly white face. Young birds browner above than adults with crisp scaly pattern on back. Breeds on Arctic tundra; generally stays on the ocean during the rest of the year. Sometimes shows up at large bodies of water inland. Found alone or in flocks.